Brock Herion

How to fix the `Already 10 Prisma Clients are actively running` error in Prisma

November 19, 2023 2 minute read

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While working with Prisma and Next.js, you may have come across this error in your terminal output

warn(prisma-client) Already 10 Prisma Clients are actively running.

This can be an annoying and somewhat tricky thing to figure out. In this article, we’ll look at why this occurs and how to fix it.

What causes this error?

This error shows up when you have a few Prisma Clients running in your app, each with their own connection pool. Normally, you would create a new Prisma instance like so

import { PrismaClient } from  "@prisma/client";
const prisma = new PrismaClient();

This is our culprit. The error can come initializing new clients multiple times or having a client be re-created from something like hot reload, and the connection is never disposed.

How to fix it

Thankfully, the fix is really simple. What we need to do is create a single place in our application where a Prisma Client is created and use that client.

// lib/prisma.ts
import { PrismaClient } from  "@prisma/client";

 // Important if you're using TypeScript!
declare global {
  var prisma: PrismaClient;

let prisma;

if (process.env.NODE_ENV === 'production') {
  prisma = new PrismaClient(["error"]);
} else {
  if (!global.prisma) {
    global.prisma = new PrismaClient(["info", "error", "warn"]);
  prisma = global.prisma;

export default prisma;

This will create a single Prisma Client that we can use throughout our application. We’re saving on a global object, expect in production where we’re instantiating the client as a normal object.

Now, you can start using your Prisma Client in anywhere in your Next.js app!


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